logic: handle java not found on windows and mac

* implemented java will not be used if it is not found on system
* add jni libraries weak linked for Mac
* use dlopen for lazy library loading
* added java path to preferences

src/lib_gui/qt/element/QtLocationPicker.cpp

@@ -41,6 +41,11 @@ void QtLocationPicker::paintEvent(QPaintEvent*)
 	style()->drawPrimitive(QStyle::PE_Widget, &opt, &p, this);
 }
 
+void QtLocationPicker::setPlaceholderText(QString text)
+{
+	m_data->setPlaceholderText(text);
+}
+
 QString QtLocationPicker::getText()
 {
 	return m_data->text();

src/lib_gui/qt/element/QtLocationPicker.h

@@ -15,6 +15,7 @@ public:
 
 	virtual void paintEvent(QPaintEvent*) override;
 
+	void setPlaceholderText(QString text);
 	QString getText();
 	void setText(QString text);
 	void clearText();

src/lib_gui/qt/window/project_wizzard/QtProjectWizzardContentPreferences.cpp

@@ -133,6 +133,32 @@ void QtProjectWizzardContentPreferences::populateForm(QGridLayout* layout, int&
 	);
 
 	row++;
+
+	layout->setRowMinimumHeight(row++, 20);
+
+	// Java
+	layout->addWidget(createFormTitle("JAVA"), row, QtProjectWizzardWindow::FRONT_COL, Qt::AlignLeft);
+	row++;
+
+	// java path
+	m_javaPath = new QtLocationPicker(this);
+	m_javaPath->setPickDirectory(true);
+	m_javaPath->setPlaceholderText("<jdk_root>");
+
+	layout->addWidget(createFormLabel("Java Path"), row, QtProjectWizzardWindow::FRONT_COL, Qt::AlignRight);
+	layout->addWidget(m_javaPath, row, QtProjectWizzardWindow::BACK_COL);
+
+	addHelpButton(
+		"Location of your java installation so that dynamic libraries of JVM can be found."
+		, layout, row
+	);
+	row++;
+
+	layout->setRowMinimumHeight(row++, 20);
+
+	// C/C++
+	layout->addWidget(createFormTitle("C/C++"), row, QtProjectWizzardWindow::FRONT_COL, Qt::AlignLeft);
+	row++;
 }
 
 void QtProjectWizzardContentPreferences::load()
@@ -159,6 +185,11 @@ void QtProjectWizzardContentPreferences::load()
 
 	m_threads->setCurrentIndex(appSettings->getIndexerThreadCount() - 1);
 	m_fatalErrors->setChecked(appSettings->getShowExternalNonFatalErrors());
+
+	if (m_javaPath)
+	{
+		m_javaPath->setText(QString::fromStdString(appSettings->getJavaPath()));
+	}
 }
 
 void QtProjectWizzardContentPreferences::save()
@@ -181,6 +212,11 @@ void QtProjectWizzardContentPreferences::save()
 
 	appSettings->setIndexerThreadCount(m_threads->currentIndex() + 1);
 	appSettings->setShowExternalNonFatalErrors(m_fatalErrors->isChecked());
+
+	if (m_javaPath)
+	{
+		appSettings->setJavaPath(m_javaPath->getText().toStdString());
+	}
 }
 
 bool QtProjectWizzardContentPreferences::check()

src/lib_gui/qt/window/project_wizzard/QtProjectWizzardContentPreferences.h

@@ -5,6 +5,7 @@
 #include <QComboBox>
 #include <QLineEdit>
 
+#include "qt/element/QtLocationPicker.h"
 #include "qt/window/project_wizzard/QtProjectWizzardContent.h"
 
 class QtProjectWizzardContentPreferences
@@ -31,14 +32,16 @@ private:
 	QLineEdit* m_fontFace;
 	QComboBox* m_fontSize;
 	QComboBox* m_tabWidth;
+
 	QComboBox* m_colorSchemes;
 	QLineEdit* m_scrollSpeed;
+	std::vector<FilePath> m_colorSchemePaths;
+	int m_oldColorSchemeIndex;
 
 	QComboBox* m_threads;
 	QCheckBox* m_fatalErrors;
 
-	std::vector<FilePath> m_colorSchemePaths;
-	int m_oldColorSchemeIndex;
+	QtLocationPicker* m_javaPath;
 };
 
 #endif // QT_PROJECT_WIZZARD_CONTENT_PREFERENCES_H